1. Field of the Invention
This invention relates to a control system, and more particularly to a control system for efficiently controlling an intermittently energized device.
2. Description of the Prior Art
For example, a printer device for printing characters on recording paper in dot matrix patterns has heretofore effected such character printing with a pulsating current intermittently supplied to printing means thereof such as a thermal head or the like.
The drive control system heretofore provided to energize the printing means in such printer device has been such that the quiescent time of the thermal head is set to a sufficiently great value with respect to the time during which the pulsating current is supplied to the thermal head, thereby preventing the overheating of the thermal head which would result in serious accidents. However, should something be wrong with the print signal or the drive control system to permit a great current to be continuously applied to the thermal head, such head would be burnt out. More seriously, this may further result in destruction of the entire device.
To avoid the occurrence of such accidents, it has heretofore been the practice to provide a temperature fuse adjacent to the thermal head so as to cut off the power supply to the thermal head in an emergency to prevent the expansion of the accident. However, this has only been effective to limit the damage imparted to the subject to be controlled such as thermal head, and has not been perfect in protecting the entire device.